How fast is a fastball pitch?

Answer 1

The speed of a fastball is dependent on the pitcher throwing the pitch. At the major league level, fastball can vary in speed by 15-20mph between different pitchers. The hardest throwers have been credited with speeds exceeding 100mph, but some pitchers can barely reach 90mph. The main difference between a fastball and other pitches is how they are thrown. A fastball is thrown similarly to the natural motion of throwing a ball, allowing the ball to roll off the fingers as it is released, imparting backspin to the ball, which provides a small amount of lift, and reduces air resistance. This lift allows the pitch to have a straighter line to the plate. The more natural motion is the primary reason for the characteristic high speed of the fastball. Curve balls are thrown with the ball rolling off the thumb, with a snap of the wrist, imparting a forward spin, causing the ball to lose lift, resulting in the characteristic "curve" of the curve ball. This motion is very unnatural, and a drop-off in speed is the result.